The same tea party wave swept them into the Senate last year, but freshman phenoms Rand Paul and Marco Rubio couldn’t be more different in how they’ve approached their anti-spending mandate in Washington.

Paul, a Kentucky Republican, is blazing an outsider’s path, ruffling Senate traditions and proposing hopeless bills and resolutions that are ignored by leaders but cheered by his activist followers. Rubio has quickly worked to make himself an establishment favorite, playing the insider’s game while drawing crowds of grass-roots activists back home in Florida.

The divergent paths taken by two of the Senate’s biggest stars cut to the vexing questions facing the tea party as it matures and enjoys elected influence in Congress: Do they work the system, make deals and try to change things from within? Or do they dig in and say no to everything that falls short of their dramatic vision for shaking up Washington?

Rubio is betting heavily on the insider’s path — even making a few subtle moves that created daylight between him and Paul. Rubio refused to join Paul in the Senate tea party caucus, and earlier this month he sent a letter to the other GOP freshmen touting aid to Israel — after Paul called for an end to all U.S. foreign aid.

Matt Kibbe, president of the tea-party-affiliated FreedomWorks, said both styles can be effective, but he suggested the approach employed by Rubio, a former Florida House speaker, will help take the tea party to its third act: enacting legislation and reforms.

“The first iteration was a protest movement where we were simply banging on the castle doors trying to get someone to pay attention to our agenda, then there was the get-out-the-vote machine of the November election and now we’re in a legislative mode,” said Kibbe, whose group was founded by former House Majority Leader Dick Armey.

“Every agenda needs a guy willing to stand across the railroad tracks and say, ‘Stop this train’ — that is Rand’s approach. But once you stop the train, you need to pull together a winning coalition to pass legislation.”

Paul, however, seems to be relishing his role as a rabble-rouser, recently telling CNN that “the people of Kentucky elected me to shake things up.” His spokeswoman, Moira Bagley, said Paul believes a “bold approach” is required to tackle the debt crisis, balance the budget and reduce the size of government. But bold is one thing — his budget proposal to slash $500 billion in one year is a whole different level of thinking not shared by any other senator.

“I’ve heard members say, ‘I believe in what Rand Paul is trying to do and agree with his end goal, but I don’t like how he’s trying to get there,’” one Senate GOP aide said. “Marco Rubio is advocating principles of the people within the fringe elements but not being pigeonholed by that label.”

In January, Paul co-founded the Senate Tea Party Caucus, a move that irritated some senior senators who felt it would fracture the Republican Conference. His budget plan would choke off all foreign aid, including security funding for Israel, a longtime GOP priority. And this month, Paul threatened to block a small-business bill until Senate leaders called a vote on his unrelated Libya resolution.

Rubio has set off down a different path. He rebuffed an invitation to join Paul’s tea party caucus, circulated a letter among his freshman colleagues reaffirming the GOP’s pro-Israel stance and joined all but 10 senators in opposing Paul’s resolution objecting to the president’s authority to unilaterally attack the Libyan regime.

He’s also earning the trust of leadership. During the times he’s voted against his leaders, Rubio’s made sure to personally notify them in advance — like he did this month when he opposed the bipartisan 2011 budget bill.

“He’s respectful of people [who] have been here awhile, but I don’t sense any timidity in standing for what he believes in. That’s a good way to operate,” Alabama Sen. Jeff Sessions, the top Republican on the Budget Committee, recently told POLITICO.

“He understands that if you want to accomplish goals, being inside the boat and rowing with the boat is a lot easier than being outside and pushing it,” said GOP strategist Rob Collins, who just stepped down as president of the conservative American Action Network, an outside group that spent hundreds of thousands of dollars last year to help elect Rubio.

“He would express that his constituents are better served by working with folks than against folks.”

But as he’s endeared himself to party leaders, Rubio has continued to court the grass-roots activists who helped catapult him into the Senate last year. Rubio spoke to thousands of tea partiers during “Tax Day” rallies in Orlando and Tampa, receiving a standing ovation when he explained that he voted against the 2011 budget because it didn’t cut enough.

“Let me be fair. I think our leaders up there, a lot of them worked very hard. They think they did the best they could. I get all that, but let me tell you something. We’re running out of time,” Rubio told a crowd that had packed an outdoor pavilion in Orlando.

“This is a major, major, major moment in American history, and we no longer have the luxury of small solutions to this big problem.”

Local tea party leaders don’t seem to mind Rubio’s decision to skip the Senate Tea Party Caucus founded by Sens. Jim DeMint of South Carolina and Mike Lee of Utah. And they certainly don’t believe Rubio has been co-opted by the GOP establishment he ran against in the 2010 campaign.

“We know where he stands. We know where his heart is. We know how he’s voted,” said Ron McCoy, a West Orlando Tea Party co-founder who attended the Orlando rally, where he met Rubio for the first time.

“He has remained his own man,” added Tom Gaitens, co-founder of the Tampa Tea Party. “We’ve got a great distrust of the Beltway system turning people into Stepford senators and congressmen. We like Marco’s independence from the process.”

Still, Gaitens points out the grass-roots movement is bigger than any one person — even Rubio. “Just because he is with us today doesn’t mean we won’t hold his tail to the fire tomorrow,” Gaitens said.

Rubio and Paul are also distinctly different personalities.

Rubio, the 39-year-old son of Cuban immigrants, has been promoted from Day One as a future star of the party and usually appears on GOP short lists of 2012 vice presidential candidates. Paul, a Bowling Green eye surgeon, has taken up the outsider libertarian approach of his father, Rep. Ron Paul (R-Texas), which has an almost cult-like national grass-roots following yet is largely dismissed in the halls of Congress when it comes to legislating.

At times, it seems Rubio has tried to marginalize Paul.

Rubio once casually referred to Paul’s tea party caucus as a “little club.” And Rubio circulated his Israel letter earlier this month knowing that Paul opposed all foreign aid and likely would not sign. The Florida senator also limited it to a small group — the 13 Republican freshmen — a decision that painted Paul as out of touch on the issue.

However, the two downplayed any talk of a rivalry, saying they get along well personally and that the GOP provides plenty of room for diverse approaches and opinions.

“We’re a big party, man. There’s a variety of views in our party on a bunch of issues. The Republican Party’s a big tent,” Rubio told POLITICO in an interview at the Capitol. “There’s gonna be divergence of opinion on different issues — that’s normal but not by design. It’s just what we believe in.”

Paul said he wasn’t bothered by Rubio passing on the tea party caucus, describing their relationship as “cordial.” In fact, staffers and reporters recently spotted Paul, Rubio, Lee and DeMint sharing a light-hearted moment on the Senate floor.

“I have nothing but good things to say about him,” Paul told POLITICO. “We get along fine, and I think there will be things we work on together.”